随机字符串生成器返回相同的字符串

我已经开发了一个随机字符串生成器，但它的行为并不像我所希望的那样。我的目标是能够运行两次，并生成两个不同的四字符随机字符串。但是，它只生成一个四个字符的随机字符串两次。

下面是代码和输出示例:

private string RandomString(int size)
{
    StringBuilder builder = new StringBuilder();
    Random random = new Random();
    char ch;
    for (int i = 0; i < size; i++)
    {
        ch = Convert.ToChar(Convert.ToInt32(Math.Floor(26 * random.NextDouble() + 65)));                 
        builder.Append(ch);
    }

    return builder.ToString();
}

// get 1st random string 
string Rand1 = RandomString(4);

// get 2nd random string 
string Rand2 = RandomString(4);

// create full rand string
string docNum = Rand1 + "-" + Rand2;

.．.输出如下:UNTE-UNTE .．.但它应该看起来像这个UNTE-FWNU

如何确保两个明显随机的字符串?

当前回答

public static class StringHelpers
{
    public static readonly Random rnd = new Random();

    public static readonly string EnglishAlphabet = "abcdefghijklmnopqrstuvwxyz";
    public static readonly string RussianAlphabet = "абвгдеёжзийклмнопрстуфхцчшщъыьэюя";

    public static unsafe string GenerateRandomUTF8String(int length, string alphabet)
    {
        if (length <= 0)
            return String.Empty;
        if (string.IsNullOrWhiteSpace(alphabet))
            throw new ArgumentNullException("alphabet");

        byte[] randomBytes = rnd.NextBytes(length);

        string s = new string(alphabet[0], length);

        fixed (char* p = s)
        {
            for (int i = 0; i < s.Length; i++)
            {
                *(p + i) = alphabet[randomBytes[i] % alphabet.Length];
            }
        }
        return s;
    }

    public static unsafe string GenerateRandomUTF8String(int length, params UnicodeCategory[] unicodeCategories)
    {
        if (length <= 0)
            return String.Empty;
        if (unicodeCategories == null)
            throw new ArgumentNullException("unicodeCategories");
        if (unicodeCategories.Length == 0)
            return rnd.NextString(length);

        byte[] randomBytes = rnd.NextBytes(length);

        string s = randomBytes.ConvertToString();
        fixed (char* p = s)
        {
            for (int i = 0; i < s.Length; i++)
            {
                while (!unicodeCategories.Contains(char.GetUnicodeCategory(*(p + i))))
                    *(p + i) += (char)*(p + i);
            }
        }
        return s;
    }
}

你还需要这个:

public static class RandomExtensions
{
    public static string NextString(this Random rnd, int length)
    {
        if (length <= 0)
            return String.Empty;

        return rnd.NextBytes(length).ConvertToString();
    }

    public static byte[] NextBytes(this Random rnd, int length)
    {
        if (length <= 0)
            return new byte[0];

        byte[] randomBytes = new byte[length];
        rnd.NextBytes(randomBytes);
        return randomBytes;
    }
}

这:

public static class ByteArrayExtensions
{
    public static string ConvertToString(this byte[] bytes)
    {
        if (bytes.Length <= 0)
            return string.Empty;

        char[] chars = new char[bytes.Length / sizeof(char)];
        Buffer.BlockCopy(bytes, 0, chars, 0, bytes.Length);
        return new string(chars);
    }
}

2013-04-16 09:24:46

其他回答

public static class StringHelpers
{
    public static readonly Random rnd = new Random();

    public static readonly string EnglishAlphabet = "abcdefghijklmnopqrstuvwxyz";
    public static readonly string RussianAlphabet = "абвгдеёжзийклмнопрстуфхцчшщъыьэюя";

    public static unsafe string GenerateRandomUTF8String(int length, string alphabet)
    {
        if (length <= 0)
            return String.Empty;
        if (string.IsNullOrWhiteSpace(alphabet))
            throw new ArgumentNullException("alphabet");

        byte[] randomBytes = rnd.NextBytes(length);

        string s = new string(alphabet[0], length);

        fixed (char* p = s)
        {
            for (int i = 0; i < s.Length; i++)
            {
                *(p + i) = alphabet[randomBytes[i] % alphabet.Length];
            }
        }
        return s;
    }

    public static unsafe string GenerateRandomUTF8String(int length, params UnicodeCategory[] unicodeCategories)
    {
        if (length <= 0)
            return String.Empty;
        if (unicodeCategories == null)
            throw new ArgumentNullException("unicodeCategories");
        if (unicodeCategories.Length == 0)
            return rnd.NextString(length);

        byte[] randomBytes = rnd.NextBytes(length);

        string s = randomBytes.ConvertToString();
        fixed (char* p = s)
        {
            for (int i = 0; i < s.Length; i++)
            {
                while (!unicodeCategories.Contains(char.GetUnicodeCategory(*(p + i))))
                    *(p + i) += (char)*(p + i);
            }
        }
        return s;
    }
}

你还需要这个:

public static class RandomExtensions
{
    public static string NextString(this Random rnd, int length)
    {
        if (length <= 0)
            return String.Empty;

        return rnd.NextBytes(length).ConvertToString();
    }

    public static byte[] NextBytes(this Random rnd, int length)
    {
        if (length <= 0)
            return new byte[0];

        byte[] randomBytes = new byte[length];
        rnd.NextBytes(randomBytes);
        return randomBytes;
    }
}

这:

public static class ByteArrayExtensions
{
    public static string ConvertToString(this byte[] bytes)
    {
        if (bytes.Length <= 0)
            return string.Empty;

        char[] chars = new char[bytes.Length / sizeof(char)];
        Buffer.BlockCopy(bytes, 0, chars, 0, bytes.Length);
        return new string(chars);
    }
}

2013-04-16 09:24:46

以下是我对目前公认答案的修改，我认为它更快更短:

private static Random random = new Random();

private string RandomString(int size) {
    StringBuilder builder = new StringBuilder(size);
    for (int i = 0; i < size; i++)
        builder.Append((char)random.Next(0x41, 0x5A));
    return builder.ToString();
}

注意，我没有使用所有的乘法，math。floor()， Convert等。

编辑:随机的。Next(0x41, 0x5A)可以更改为任何范围的Unicode字符。

2012-11-01 02:26:33

我的RandomString()方法来生成一个随机字符串。

private static readonly Random _rand = new Random();

/// <summary>
/// Generate a random string.
/// </summary>
/// <param name="length">The length of random string. The minimum length is 3.</param>
/// <returns>The random string.</returns>
public string RandomString(int length)
{
    length = Math.Max(length, 3);

    byte[] bytes = new byte[length];
    _rand.NextBytes(bytes);
    return Convert.ToBase64String(bytes).Substring(0, length);
}

2013-06-25 07:17:22

我添加了使用Ranvir溶液选择长度的选项

public static string GenerateRandomString(int length)
    {
        {
            string randomString= string.Empty;

            while (randomString.Length <= length)
            {
                randomString+= Path.GetRandomFileName();
                randomString= randomString.Replace(".", string.Empty);
            }

            return randomString.Substring(0, length);
        }
    }

2012-03-27 16:25:13

如果您想为强密码生成一串数字和字符。

private static Random random = new Random();

private static string CreateTempPass(int size)
        {
            var pass = new StringBuilder();
            for (var i=0; i < size; i++)
            {
                var binary = random.Next(0,2);
                switch (binary)
                {
                    case 0:
                    var ch = (Convert.ToChar(Convert.ToInt32(Math.Floor(26*random.NextDouble() + 65))));
                        pass.Append(ch);
                        break;
                    case 1:
                        var num = random.Next(1, 10);
                        pass.Append(num);
                        break;
                }
            }
            return pass.ToString();
        }

2010-10-14 17:58:38

随机字符串生成器返回相同的字符串

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